The present invention relates generally to chucks for use with drills or electric or pneumatic power drivers. The present invention relates to chucks of the keyed type or of the keyless type, which may be tightened or loosened by hand.
Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools on such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones, and other cutting or abrading tools. Since the tool shanks may be of varying diameter or of polygonal cross section, the device is usually provided with a chuck adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore or any other suitable means.
A variety of chuck types have been developed in which a gripping mechanism is actuated by relative rotation between a chuck body and a sleeve. In an exemplary oblique jawed chuck, for example, a body member includes three passageways disposed approximately 120.degree. apart from each other. The passageways are configured so that their center lines meet at a point along the chuck axis forward of the chuck body. Three jaws are constrained by and movable in the passageways to grip a cylindrical tool shank disposed approximately along the chuck center axis. A nut rotates about the chuck center and engages threads on the jaws so that rotation of the nut moves the jaws in either direction in the passageways. The body is attached to the drive shaft of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaws into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship.
In a keyed chuck, a chuck key is received in a radial hole in the nose section of the body and includes teeth which engage corresponding teeth on the nut, for example, so that rotation of the key rotates the nut about the body. On the other hand, a chuck may be keyless if it is rotated by hand. One example of such a chuck is disclosed in U.S. Pat. No. 5,125,673 entitled "Non-Impact Keyless Chuck," commonly assigned to the present assignee and the entire disclosure of which is incorporated by reference herein. Various configurations of keyed and keyless chucks are known in the art and are desirable for a variety of applications.
As should be understood by those of ordinary skill in this art, the nut is typically of a one piece construction or an axially split construction. A split nut typically comprises two semi-circular halves received in a circumferential groove in the body. While the groove axially retains the nut, a mechanism must be provided to radially retain the halves in place. Such mechanism may include, for example, a sleeve member, a retaining band or a retaining band co-molded in the sleeve member. In contrast, a one piece nut is radially self-contained but generally must be axially retained with respect to the body. This is often accomplished by a retention mechanism mounted on or about the body nose section.